To avoid an out of range error you might need to reduce your courant number below 0.5. Weller et. al. (Proc. of Comb. Inst. 1998) mention that a CFL < 0.5 is required for stability, CFL < 0.2 for accuracy. This has also been mentioned on the message board.

Are you using a fixed time-step or having the solver select a time-step based on a CFL condition ?

To alter the ignition you might try adding additional ignition sites and/or changing the parameters of the existing ignition sites.

I want to know what is the relationship between these parameters in ignitions sites field:

duration 0.01;
strength 4;

I pretty sure that duration is the time in sec. during which the sparkle takes place. but if I am wrong (please correct me) . If I increase the duration time i also have to increase the strength in order to get the same result , the point is that i have no idea what is the relationship , what is the meaning of strength anyways

the maxCo is 0.1 (in fact the last max Courant was 0.099034) the last residual for p, Ux, Uy,and k were 2.55e-08,2.44e-08,6.55e-09, 7.5e-10.

Something I can not still understand. In the previous time step the min temp either in T or Tu field were bigger than 200 , and in the next time step,(with a deltaT = 8.14815e-08 ) in one point the temperature simply dropped to -736.126 (how could this change happened in such small deltaT and Courant number)

and 3 time steps before the error i get Solution singularity for Xi and b , not sure if this is directly related , because I got the same singularity solution warning for Xi in the first Time Step

Hi Foamers,
i´m a new foamer and wondering if anybody has found a satisfying answer to the problem with the error from janafThermo:

I´m currently working on a combustion induced vortex breakdown with XiFoam respectively myXiFoam (within this solver i have changed the calculation of the desity to be only depending on the compressibility) . I´m using a 2D mesh (Axi-symmetric geometry using the wedge patch type) and running with low Courrant numbers 0.2<Co<0.5.